Radar level gauging systems can be arranged in a tank, in order to provide information about process variables of a product in the tank. Examples of process variables that may be determined by such sensors are filling level, product composition, inflow, etc.
In such gauging systems, function independence is sometimes required. For example, safety regulations require that a high level alarm sensor and/or an overfill alarm sensor function independently of a level measurement sensor as well as of each other. Functional independence here means that a fault in one system does not render the other system(s) inoperative.
Such independence can be achieved by having several RLG units galvanically isolated from each other. This results in a system where each RLG unit is implemented with fully redundant hardware and software in order to meet both operational and service requirements. In case of level measurement and alarms, each RLG unit within the sensor system needs components for measuring the filling level, and each RLG unit needs an interface for receiving configuration data. Such RLG systems are used especially (but not exclusively) in marine applications, e.g. mounted on board tank ships.
In the case of advanced gauging systems, a large number of configuration parameters are required, and service commands are communicated to the sensor in order to determine its status. In systems with several independent sensors of this or similar type, the independency requirements make the system complex and expensive. In addition, operation of the system becomes time consuming and difficult, as large amounts of data must be communicated to each sensor.